Electron Capture Into High-Lying Rydberg States in Collisions Between Multiply Charged Ions and H2

Electron capture in collisions between multiply charged ( v ∼ v 0 ) ions and H 2 has been shown to lead to a strong population of highly excited Rydberg states. Accordingly, relative intensities of the spectral lines corresponding to transitions from these states can be measured under single-collision conditions. The dominating transitions for ions with large ( n, l ) values are Δ n = 1 transitions, which for ions with charge states ∼ 15 and n values from 10 to 15 result in light emission in the visible region. The lines corresponding to transitions between two n values are found to present structure, which indicates a non-degeneracy according to different l values. This l splitting is assumed to be caused by core polarization, and it is found that capture predominantly takes place to l = n - 1 states. The dipole polarizability for Au 13+ is found to be be 0.9 a 0 3 .